1960s-80s: Zika detected in mosquitoes and monkeys across equatorial Africa

1969–83: Zika found in equatorial Asia, including India, Indonesia, Malaysia and Pakistan

2007: Zika spreads from Africa and Asia, first large outbreak on Pacific island of Yap

2012: Researchers identify two distinct lineages of the virus, African and Asian

2013–14: Zika outbreaks in French Polynesia, Easter Island, the Cook Islands and New Caledonia. Retrospective analysis shows possible link to birth defects and severe neurological complications in babies in French Polynesia

March 2, 2015: Brazil reports illness characterized by skin rash in northeastern states

July 17: Brazil reports detection of neurological disorders in newborns associated with history of infection

Feb. 12: Brazil investigating potential link between Zika infections and 4,314 suspected cases of microcephaly. Of those, 462 confirmed as microcephaly and 41 determined to be linked to virus

Feb. 17: Brazil investigating potential link between Zika and 4,443 suspected cases of microcephaly. Of those, 508 confirmed as microcephaly and most of those cases are linked to the virus. WHO seeks $56 million to fight Zika.

Feb. 18: CDC adds Aruba and Bonaire to countries and territories with active outbreaks, bringing total to 32.

Feb. 23: CDC investigating 14 cases of possible sexual transmission of Zika. CDC also adds Trinidad and Tobago and Marshall Islands to countries and territories with active outbreaks, bringing total to 34.

Feb. 25: Brazil says confirmed microcephaly cases number more than 580 and considers most of them to be related to Zika infections in the mothers. Brazil is investigating an additional 4,100 suspected cases of microcephaly.

Feb. 27: France detects first sexually transmitted case of Zika.

Feb. 29: CDC adds St. Maarten, and Saint Vincent and the Grenadines to countries and territories with active outbreaks, bringing total to 36.

March 1: Brazil says confirmed microcephaly cases rose to 641 and considers most of them to be related to Zika infections in the mothers. Brazil is investigating an additional 4,222 suspected cases of microcephaly.

March 8: WHO advises pregnant women to avoid areas with Zika outbreak and said sexual transmission of the virus is “relatively common.”

March 9: CDC adds New Caledonia to countries and territories with active outbreaks, bringing total to 37.

March 15: Cuba reports first case of Zika contracted in the country.

March 16: Cape Verde identifies first case of microcephaly.

March 18: CDC says during Jan. 1, 2015 to Feb. 26, 2016, 116 residents of the United States had evidence of recent Zika virus infection based on laboratory testing.

Brazil says confirmed microcephaly cases rose to 863 and considers most of them to be related to Zika infections in the mothers. Brazil is investigating an additional 4,268 suspected cases of microcephaly.

March 19: CDC adds Cuba to countries and territories with active outbreaks, bringing total to 38.

March 21: South Korea confirms first case of Zika.

March 22: CDC adds Dominica to countries and territories with active outbreaks, bringing total to 39. Bangladesh confirms first case of Zika virus.

Brazil says confirmed microcephaly cases rose to 907 and considers most of them to be related to Zika infections in the mothers. Brazil is investigating an additional 4,293 suspected cases of microcephaly.

March 29: Brazil says confirmed microcephaly cases rose to 944 and considers most of them to be related to Zika infections in the mothers. Brazil said the number of suspected cases of microcephaly dropped slightly to 4,291.

March 31: According to the World Health Organization, there is a strong scientific consensus that Zika can cause the birth defect microcephaly as well as Guillain-Barre syndrome, a rare neurological disorder that can result in paralysis, though conclusive proof may take months or years.

April 1: CDC adds Kosrae, Federated States of Micronesia to countries and territories with active outbreaks, bringing total to 40.

April 4: CDC adds Fiji to countries and territories with active outbreaks, bringing total to 41.

April 5: Vietnam reports first Zika infections.

April 6: Brazil says confirmed microcephaly cases rose to 1,046 and considers most of them to be related to Zika infections in the mothers. The number of suspected cases of microcephaly dropped to 4,046.

April 7: St. Lucia confirms first two cases of Zika, contracted locally.

April 12: Brazil says confirmed microcephaly cases rose to 1,113 and considers most of them to be related to Zika infections in the mothers. The number of suspected cases of microcephaly dropped to 3,836. It was the second week in a row that the overall total figure fell.

April 13: The U.S. Centers for Disease Control and Prevention concluded that infection with the Zika virus in pregnant women is a cause of the birth defect microcephaly and other severe brain abnormalities in babies. The CDC said now that the causal relationship has been established, several important questions must still be answered with studies that could take years.

CDC adds St. Lucia to countries and territories with active outbreaks, bringing total to 42.

April 14: Colombia confirms two microcephaly cases linked to Zika.

April 18: Peru reports first case of sexually transmitted Zika virus.

CDC adds Belize to countries and territories with active outbreaks, bringing total to 43.

April 19: Chilean authorities find Zika mosquito for first time in decades.

April 25: Canada confirms first sexually transmitted Zika case.

April 26: Brazil says the number of confirmed cases of microcephaly climbed to 1,198 from 1,168 in the week through April 23, but suspected ones under investigation continued to decline to 3,710 from 3,741 a week ago.

Brazil registered 91,387 likely cases of the Zika virus from February until April 2, the health ministry said, in its first national report on the epidemic.

April 29: Puerto Rico reports first death related to Zika, according to the CDC. The country also confirmed 683 Zika cases, including 65 pregnant women, and five suspected cases of Guillain-Barre syndrome from Zika, the CDC reported.

May 4: Panama confirms four microcephaly cases tied to Zika.

May 6: Spain gets first case of Zika-related brain defect in a fetus.

May 9: CDC adds Papua New Guinea, Saint Barthelemy and Peru to countries and territories with active outbreaks, bringing total to 46.

Honduras suspects first case of microcephaly in Zika patient.

May 11: Brazil says the number of confirmed cases of microcephaly dropped to 1,326 in the week through May 7 as doctors and Brazilian health officials find that some suspected cases of microcephaly are not the disorder. Suspected ones under investigation continued to decline to 3,433.

May 12: CDC adds Grenada to countries and territories with active outbreaks, bringing total to 47.

May 13: Puerto Rico reports first case of Zika-related microcephaly.

May 20: WHO says an outbreak of Zika virus on the African island chain of Cape Verde is of the same strain as the one blamed for birth abnormalities in Brazil.

May 24: Brazil reports the number of confirmed cases of microcephaly at 1,434 for the latest week to May 21. Suspected ones under investigation declined to 3,257.

May 26: CDC adds Argentina to countries and territories with active outbreaks, bringing total to 48.

June 9: WHO issues updated guidelines on prevention of sexual transmission of the Zika virus, including advising women living in areas where the virus is being transmitted to delay getting pregnant.

June 14: El Salvador confirms first case of microcephaly linked to Zika.

June 23: CDC reports seven babies in the United States with microcephaly or other Zika-related birth defects such as serious brain abnormalities, and five lost pregnancies from either miscarriage, stillbirth or termination.

June 28: First baby with Zika-related birth defect microcephaly born in Florida.

June 30: CDC adds Anguilla to countries and territories with active outbreaks, bringing total to 49.

July 8: CDC confirmed that a Utah resident’s death last month is the first Zika-related death in the continental United States.

July 14: CDC adds Saint Eustatius to countries and territories with active outbreaks, bringing total to 50.

July 15: New York City’s health department reports the first female-to-male transmission of the Zika virus.

July 18: CDC reports that caregiver of Utah man who died of Zika tested positive for virus.

July 19: Florida health officials are investigating a case of Zika virus infection that does not appear to have stemmed from travel to another region with an outbreak.

July 21: CDC reports 400 pregnant women in U.S. with evidence of Zika infection, up from 346 a week ago. The health agency also reports three more babies born in U.S. with birth defects linked to the Zika virus, bringing total to 12.

Florida Department of Health said it was investigating a non travel-related case of Zika in Broward County, marking the second such case in the U.S.

July 22: New York City health officials reports first baby born with Zika-related birth defect.

July 25: Spain reports first case in Europe of baby born with Zika-related defect.

CDC issues updated recommendations for preventing and testing for Zika infection, warning that the virus can be transmitted through unprotected sex with an infected female partner.

July 26: Honduras detects 8 cases of babies with Zika-related defect.

CDC adds Saba to countries and territories with active outbreaks, bringing total to 51

July 27: Paraguay reports first cases of microcephaly linked to Zika.

July 29: Florida authorities report what is believed to be the first evidence of local Zika transmission in the continental United States.

SOURCES: World Health Organization, U.S. Centers for Disease Control and Prevention, Reuters